Graphene is a two-dimensional crystal composed of honeycomb-arranged carbon atoms. Due to its quantum transport properties, high electrical conductivity, electron mobility, and light transmissivity, graphene and related devices have become one of the hot topics in physics, chemistry, biology and materials science research. So far, there have appeared a variety of devices using graphene as basic functional unit, such as field effect transistors, solar cells, nano-generators, sensors, etc.
Quantum dot (referred as QD) is a semiconductor nanocrystal of which radius is less than or close to the exciton Bohr radius. As a quasi-zero-dimensional nanomaterial which is 1 to 10 nm in all three dimensions, QDs appear just like very tiny dot. Because QDs have dimensions comparable to de Broglie wavelength of electron, coherent wavelength and exciton Bohr radius, electrons in confined in a nanospace, resulting in a restricted electron transport and a rather short electron mean free path, enhanced electronic coherence and localization, which in turn brings about quantum confinement effect. Therefore, QDs exhibit many physical and chemical properties that are different from macroscopic materials. Due to their unique quantum size effect, QDs have been widely used in the field of optoelectronics, such as solar cells, light emitting devices, biomarkers.
In prior art, the electroluminescent layer of a quantum dot light emitting diode only comprises a quantum dot layer, However, due to the poor charge transport ability of quantum dots, the light emission efficiency of the light emitting diode is adversely affected.